Investigation on structural, optical and electrochemical behavior of NiO/ZnMn2O4ternary nanocomposites via two-step synthesis approach for supercapacitor application

The present investigation deals with the synthesis of nickel oxide (NiO)/zinc manganite (ZnMn2O4) nanocomposites (NCs) by a two-step approach. The powder X-ray diffraction (PXRD) pattern revealed the existence of face-centered cubic (FCC) phase of NiO and tetragonal rutile phase structure of ZnMn(2)O(4)in NiO/ZnMn2O4NCs. The optical properties of NiO/ZnMn2O4NCs have been investigated by the UV-diffuse reflectance Spectroscopy (UV-DRS) and photoluminescence (PL) spectral analysis. The surface morphology and elemental composition of NiO/ZnMn2O4NCs was investigated by field emission scanning electron microscope (FESEM) and energy-dispersive X-ray spectrum (EDX) analysis. The surface area and the nature of porosity of the samples were analyzed using Brunauer-Emmett-Teller (BET) method. The electrochemical properties were investigated from the cyclic voltammetry (CV), galvanostatic charge discharge (GCD) and electrochemical impedance spectroscopy (EIS) measurements. In 0.5 M potassium hydroxide (KOH) electrolyte solution, NiO/ZnMn2O4NCs exhibited higher specific capacitance of 886 F/g at a current density of 1Ag(-1)with high cyclic stability over 1000 charge-discharging cycles. Thus, the result demonstrates that the prepared NiO/ZnMn2O4NCs is a promising electrode material for future energy-storage devices.